I'm coming to a conclusion that I either put the fondant on DIRECTLY after I put the buttercream on or I let the buttercream dry some then put the fondant on?

What do you guys feel I should do?

Also, Do I need a rod for a two tier cake about 8" and 6" if I'm literally moving it probably a few feet once I'm done decorating? If I don't need one, should I just put a little buttercream icing on the spot I'm going to place the top tier so It doesn't fall and wiggle around?

I chill my cakes before adding any fondant.  I find the buttercream feels more stable at a cold temp.   I even stick my cakes back in the fridge after covered in fondant (not

air tight though....just in a cake box or on a cake stand )  Never have had any issues. 

Stacking is not my area of experience though...I have yet to do it myself so I am hoping someone else answers here so I can learn too :)

You will need dowels underneath the 6" I'd say about 3 or four. You should have a board underneath the 6" that's also 6" and put some BC on top of the dowels where you want the cake to go and then just stick it on!